Dermatomes are hand-held surgical instruments used by a physician or medical professional (hereinafter operator) for cutting thin layers or sections of skin tissue. Dermatomes are used in hospitals and other medical facilities for excising or removal of skin tissue from patients in connection with various medical procedures including split-thickness and full-thickness skin grafting, skin debriding (e.g., removal of burned skin tissue), tumor/lesion removal, and breast reduction, among other procedures. Dermatomes are also used in to remove skin tissue from deceased human or animal donors for skin grafting purposes.
Prior dermatomes included both manual operated and power operated dermatomes. Manual dermatomes typically included a fixed blade and a handle projecting from the blade. Manual dermatomes were often found tedious to use and prone to operator fatigue, especially when large sections of skin tissue needed to be removed, requiring multiple sections of skin tissue to be removed. For example, a deceased human donor may provide from 6-9 square feet of recoverable skin tissue.
It is generally desired that an excised skin section be of uniform or consistent thickness along the longitudinal extent of the skin section and across the width of the skin section. The thickness of an excised skin section is dependent on the depth of cut of the dermatome cutting blade. Use of manual dermatomes often resulted in excised skin sections of varying thickness and having irregular edges. The uniformity of the depth of cut was largely dependent on the skill of the operator. While limited numbers of manual dermatomes continue to be used, power operated dermatomes are favored in procedures where large sections of skin tissue need to be removed in an efficient manner and/or operator fatigue is an issue.
Prior power operated dermatomes typically included a reciprocating cutting blade disposed at a front or leading edge of the dermatome with a guard or depth gauge to allow the operator to set a depth of cut of the dermatome to remove a desired thickness of skin tissue. The blade was typically disposed orthogonally to a rearward extending handle or hand piece of the dermatome. Because the cutting direction of the blade of prior power operated dermatomes was forward facing, such dermatome configurations required the operator to move the dermatome in a direction generally away from the operator's body to excise or cut a section of skin tissue. This direction of movement of the operator's hand and the dermatome away from the operator's body is less natural and less precise that a direction of movement of the operator's hand and dermatome toward the operator. Moreover, in moving the dermatome away from the operator's body, the position of the dermatome tends to block the area of the skin tissue being excised from the view of the operator. This is especially problematic where the tissue to be removed is adjacent to, for example, a raised or bony prominence of the body that must be carefully navigated around with the cutting edge of the dermatome cutting blade.
Additionally, with prior power operated dermatomes, in order to cut a skin tissue section with a desired, consistent depth of cut, the angle of cut, the speed of the dermatome along the skin, and the pressure applied to the dermatome had to be carefully controlled by the operator. The angle of cut of the dermatome refers to an acute angle between the dermatome cutting blade and the skin tissue being removed or excised. If the angle of cut of the dermatome is too shallow, the desired depth of cut will not be achieved. If the angle of cut of the dermatome is too steep, gouging or trenching of the excised skin tissue will occur. Further, if the angle of cut is changed as the power operated dermatome is moved along the skin tissue, the depth of cut will vary along a longitudinal extent of the excised section of skin tissue.
The speed or rate of forward movement of prior power operated dermatomes also had to be carefully controlled by the operator. If the speed of the dermatome was too fast or too slow, the depth of cut of the excised skin section may be greater or less than the desired depth of cut as set by the operator using the dermatome depth gauge.
The operator using a typical prior power operated dermatome also was required to apply considerable pressure to the dermatome to insure that the entire extent or length of the cutting edge of the reciprocating blade remained in contact with the skin tissue. The pressure applied by the operator to the dermatome needed to remain constant. If the pressure applied by the operator to the dermatome was too high or too low during a cutting operation, the depth of cut could change and the excised skin section would have portions that were of greater or less depth than the desired depth of cut as set with the dermatome depth gauge. If the pressure applied by the operator to the dermatome was too low, the excised skin tissue may be too thin resulting in holes in the excised skin tissue and/or chattered edges.
Uniformity in the depth of cut of excised skin sections is especially important in split thickness skin grafts where it desired to remove only the outer epidermis and a portion of the dermis. Desired skin tissue thickness in a thin-type split-thickness skin graft is on the order of 0.127 to 0.304 mm. Thus, there is little margin for error where the desired skin thickness and depth of cut is very thin.
With prior dermatomes using a reciprocating blade, it was sometimes necessary for the operator to have an assistant provide counter-traction to flatten the skin surface in front of or behind the path of travel of the dermatome to allow the dermatome blade to make an initial cut. Adding an additional person to the procedure not only increases the cost of the procedure, but also increases the risk of infection and contamination due to the presence of another person in the operating or procedure room.
What is needed is a power operated dermatome wherein obtaining a desired, consistent thickness of an excised skin tissue section is less dependent on operator skill in maintaining a constant, desired angle of cut, speed and pressure on the dermatome. What is needed is a power operated dermatome that reduces operator fatigue when removing large sections of skin tissue. What is needed is a power operated dermatome that facilitates the removal of skin tissue in tight spaces and around boney prominences. What is needed is a power operated dermatome that facilitates improved control of the dermatome by the operator by moving the blade cutting edge along a path toward the operator, instead of moving the blade away from the operator. What is needed is a power operated dermatome that allows for improved visibility of the skin site being excised by the operator. What is needed is a power operated dermatome that facilitates removal of very thin layers of skin tissue and tangential excision of burn tissue. What is needed is a power operated dermatome that does not require an additional person involved in the procedure to provide counter-traction at the skin removal site to permit an initial cut to be made by the dermatome.